String test easier for patients to swallow

Jessica Chrzan

José M. Osorio, Chicago Tribune

Jessica Chrzan, 17, participated in a study to measure inflammation caused by a condition called eosinophilic esophagitis, an inflammation of the espohagus that makes it difficult for a person to swallow.

Jessica Chrzan, 17, participated in a study to measure inflammation caused by a condition called eosinophilic esophagitis, an inflammation of the espohagus that makes it difficult for a person to swallow. (José M. Osorio, Chicago Tribune)

Jessica Tobacman, Special to the Tribune

She's only 17, but Jessica Chrzan is at the forefront of an effort to do a better job of monitoring a disease that makes her nauseated.

Chrzan participated in a University of Illinois at Chicago College of Medicine study that tested a new way to measure inflammation caused by a condition called eosinophilic esophagitis, an inflammation of the espohagus that, among other effects, can make it difficult for a person to swallow. She and her 5-year-old brother, Oliver, have the disease.

As part of the study of the enterotest string test (EST), Chrzan has swallowed a capsule that contains a 90-centimeter string, one-ninth of which is pulled out of the capsule and wound around a finger. After the patient swallows the pill, the string is taped to the cheek, and the remaining string in the capsule unfurls down the gastrointestinal tract.

The string soaks up fluids in the middle of the esophagus. The researchers then measure the pH levels on different parts of the string to determine which piece of the string was in the esophagus, as opposed to the stomach, said Steven Ackerman, a professor of biochemistry and molecular genetics at UIC and co-principal investigator on the study. They then look for eosinophil proteins to determine whether or not the inflammation is active.

Researchers say the test is a less invasive way of monitoring eosinophilic esophagitis than using an endoscope, a long, thin tube attached to a camera, into the body.

Results from Ackerman's study, which were published online in the Aug. 15 edition of the journal Gut, found that EST is an effective way to monitor the inflammation, Ackerman said.

"This was a culmination of a lot of work over four years or more. We were extremely happy with the results, which were better than envisioned. The results suggested that the test is as good as a biopsy for assessing the level of inflammation in the esophagus in the disease," Ackerman said.

Chrzan said it wasn't difficult to swallow the capsule for the study.

"I'm used to swallowing pills. If you leave the string alone, it doesn't bother you," she said. Jessica said the illness makes her nauseated and causes headaches and stomachaches.

The recent paper included results from the EST as performed in 41 patients, ages 7 to 20, with the disease. Chrzan and her brother Oliver are patients at the Lurie Children's Hospital of Chicago in the eosinophilic esophagitis clinical and research program. Patients in the study were also seen at Children's Hospital Colorado, and the scientific side of the research was conducted at UIC's College of Medicine.

Ackerman cautioned that the EST cannot be used to diagnose eosinophilic esophagitis.

"It would need further study, FDA approval and fine-tuning to become a diagnostic test," he said. At this point, "the string test is a less invasive way to determine whether inflammation in the esophagus is subsiding, continuing or exacerbating."

Upcoming research will involve trying to see if the test works with adults, and researchers will also work to develop a one-hour test, rather than the overnight exam in the published study, Ackerman said.

Dr. Ikuo Hirano, a professor at the Northwestern University's Feinberg School of Medicine, said eosinophilic esophagitis is a "disease with rapidly increasing prevalence." The American Partnership for Eosinophilic Disorders estimates that more than 1 in 2,000 people have the disease.

"This is a very exciting and very important study that may change the way we manage the disease," Hirano said. "This is a minimally invasive test that is innovative and novel. There's a huge advantage in following the disease over time. It's just a matter of swallowing a string, which is much easier than a biopsy. A string is a much easier thing for patients to tolerate."